Slim Light Box,Light Box,Advertising Signs,Ultra-Thin Light Box Guangzhou Jinshiming advertising equipment Co., Ltd , https://www.jsmlightbox.com
The high-frequency switch circuit is mainly composed of a rectification filter circuit, a full bridge conversion circuit, a PWM control circuit, a voltage regulator, a voltage limiting circuit, a steady current, a current limiting circuit, a protection circuit, and an auxiliary power supply circuit.
After the three-phase power grid (or single-phase) voltage is switched by the power supply, it is rectified and filtered, and the obtained 520Vdc (single-phase 300Vdc) smooth DC voltage is supplied to the inverter circuit.
The inverter circuit is mainly composed of a high-power IGBT module (or field-effect MOSFET module) as a full-bridge converter circuit. When the PWM output control signal drives the power module separately through the isolated driver, the two sets of diagonal tubes are alternately turned on to generate a high frequency pulse voltage in the primary of the high frequency transformer. The secondary voltage is transformed by the high frequency transformer and then rectified to provide energy to the load. .
The output terminals are connected with feedback circuits such as voltage regulation, current limiting, steady current, and voltage limiting. When placed in regulation, the regulated and current-limiting circuit is active. When the output voltage rises or falls, the sampling voltage is compared with the reference voltage through the internal voltage comparator of the voltage regulator circuit. The error signal voltage is applied to the PWM control circuit. , Make PWM output pulse width to make corresponding change, thus stabilize the output voltage, if the load current is too high, the current limit circuit works, make the output current limit in the current limit setting value.
Similarly, in the steady flow state, the steady current circuit acts to stabilize the output current within the set value, and when overvoltage, the voltage limiting circuit clamps the output voltage at the limited voltage value. When there is an abnormal situation (such as input over-voltage or under-voltage, over-current or overheating, etc.) to generate a protection signal to the protection control circuit, the protection circuit outputs a voltage to the PWM circuit, so that the PWM circuit stops outputting, thereby achieving the purpose of protection.
The AC power supply is connected to the rectifier module, which is converted into a DC after filtering and a three-phase full-wave rectifier, and then it is connected to a high-frequency inverter circuit, converts the DC to high-frequency AC, and finally outputs the high frequency transformer, rectifier bridge, and filter. Smooth DC.
January 21, 2024